A wind turbine with horizontal axis includes the main components turbine blades, a nacelle on which the blades are mounted and in which the electric generator is housed, a tower, at the top of which the nacelle is mounted and power control module arranged at the bottom of the tower. Transportation of the components and the assembling of these are circumstantial due to the high weight and the large dimensions and represent a considerable part of the costs for erecting a wind turbine. It is therefore important to arrange for the transportation and installation to be as rational as possible. The general object of the present invention is to attain improvements in this respect, in particular with regards to the power control module and the tower and the relation between these components.
The power control module contains the equipment required for the control of the turbine and for transferring the generated current to an appropriate electric output for the grid. The PCM thus may include a transformer, a converter, internal power supply and other mechanical and electrical accessories as well as a structural framework including platforms. The PCM may be divided into compartments arranged above each other, e.g. three compartments. Typically the transformer may be located in the lowermost compartment, the converter in the intermediate compartment and other equipment and sub-system in the uppermost compartment.
Traditionally the PCM is mounted on a foundation at the erection site and then the tower is mounted around it or a section of the tower is mounted on the foundation and the PCM is lowered into the tower section. This in many cases is a troublesome and time-consuming procedure, in particular at off-shore applications and at other windy places which for obvious reasons often is chosen.
EP 1788242 discloses an example of this technique, where a tower section is attached to the foundation. The tower section has supports on which platforms are lowered down to rest on the support, and the equipment is arranged on the platforms. Another example is disclosed in EP 2280168. Further similar arrangements are disclosed in EP 2108816, WO 2010103114, WO 2012130245 and DE 102010053360. EP2093417 discloses a preassembling of electronic subsystems onto a tower section.